Generally, a flexible printed circuit board is a bendable board based on a thin insulating film on which a circuit pattern is formed. At present, flexible printed circuit boards find applications in many fields including mobile electronic equipment, and automatic instruments and displays in which some electronic parts must be bent or flexible for their operation.
Particularly, there has been a sharp demand on flexible printed circuit boards for mobile terminals such as smart phones. For example, flexible printed circuit boards are used in NFC (Near Field Communication) antennas or digitizers of mobile terminals.
When installed in a display panel of electronic equipment, such as cellular phones, PDAs, laptop computers, etc., a digitizer functions to recognize and represent coordinates of touch points on the display panel, allowing for the natural representation of written letters or notes on the display panel.
Accordingly, the size of digitizers complies with that of display panels. With the tendency of display panels toward enlargement, such as in smart phones, tablet PCs, outdoor advertisement displays, etc., digitizers have gradually increased in size.
Typically, a flexible printed circuit board is manufactured by etching a copper foil laminated on a flexible insulation film, or by printing conductive paste or ink into a circuit pattern on an insulation film and then plating the circuit pattern.
However, such an etching or plating process makes the manufacture of flexible printed circuit boards complex and increases the production cost.